Abstract
Purpose: :
The purpose of this report is to review two new cases of unilateral traumatic enucleation and to compare these findings to previously published case reports.
Methods: :
The records of two traumatic enucleation cases were retrospectively reviewed. In addition, results of our literature search (English language) of all cases of unilateral traumatic enucleation that provided both a description of the optic nerve that was transected and a contralateral visual field exam were compared in a meta analysis.Results (New Case Reports):Case 1 involves a 47 year old male who was assaulted and sustained injury to his left eye. Radiologic imaging and surgical exploration of the orbit failed to identify either the globe or the optic nerve. They were presumed to have been transected at or near the optic canal which would make the length of nerve at least 40-50mm. A follow-up Humphrey visual field demonstrated a complete contralateral temporal hemianopsia.Case 2 involves a 38 year old male who was hit in his left eye by a drill. Surgical exploration revealed that the globe was laterally subluxed with 50 millimeters in length of optic nerve still attached to it. A follow-up Humphrey visual field demonstrated a complete contralateral temporal hemianopsia.
Discussion: :
A thorough review of the literature produced 15 other cases of unilateral traumatic enucleation with a description of the injured optic nerve following the transection and an accompanying contralateral visual field exam. Ten cases reported temporal field loss contralateral to the injured eye and all 10 described an optic nerve transection 40 mm and longer. This pattern could be the result of lesions occurring in either one or two locations. If this is the result of one lesion, as we believe, we can further delineate the pattern of vision loss into two categories. Two of the cases resulted in a superiotemporal field loss, which is consistent with an anterior junctional syndrome in which inferionasal fibers of the contralateral optic nerve decussate in the vicinity of the ipsilateral optic nerve/chiasm junction. These fibers may have been damaged as a result of direct transection or mechanical traction causing a contusion necrosis. Eight of the cases however displayed a temporal hemianopsia suggesting a lesion in the center of the chiasm. This may have been due to a sagittal tear of the chiasm, contusion necrosis or damage to the vessels supplying this area. There are no pathological or autopsy results to confirm this.
Conclusions: :
Traumatic enucleation of the eye with an accompanied optic nerve transection greater than or equal to 40mm in length is associated with a contralateral temporal visual field anopsia.
Keywords: optic nerve • trauma • visual fields